Seatbelt usage detection system

ABSTRACT

A system for detecting proper usage of a seatbelt in a vehicle by an operator of the vehicle is provided. The seatbelt usage detection system includes a first communication device arranged on the seatbelt and a second communication device. One of the first and second communication devices is a transmitter and the other of the first and second communication devices is a receiver. The receiver and transmitter are capable of establishing a communication link with each other. The second communication device is arranged in the vehicle so as to be able to establish a communication link with the first communication device of a predetermined signal strength upon proper fastening of the seatbelt around the body of an operator. The system also includes a processing unit for monitoring the signal strength of the communication link between the first and second communication devices and for providing a signal that the seatbelt is unfastened when the signal strength is less than the predetermined signal strength.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This patent application claims the benefit of U.S. ProvisionalPatent Application No. 60/340,037, filed Oct. 30, 2001.

FIELD OF THE INVENTION

[0002] This invention relates generally to a seatbelt assembly and, moreparticularly, to a detection system for confirming that a driverproperly fastens and uses the seatbelt.

BACKGROUND OF THE INVENTION

[0003] Seatbelts have been widely used in the United States since the1960's. Their usefulness in protecting lives has been demonstrated manytimes over. However, many individuals still refuse to use seatbelts,leading to many injuries and fatalities that could otherwise be avoided.This failure to use seatbelts is exacerbated in the operation ofindustrial equipment such as vehicles used in commercial enterprises,factories, construction sites and mines. As will be appreciated,accidents involving such vehicles are potentially more dangerous thenthose involving passenger vehicles.

[0004] To help avoid potentially serious injuries as well as stiffpenalties for violations of workplace safety regulations, e.g., MineSafety and Health Administration (MSHA); Occupational Safety and HealthAdministration (OSHA); etc., employers often take actions to ensure thattheir employees utilize seatbelts while operating motorized vehicles.Several methods for ensuring that seatbelts are correctly used have beentried or proposed. These include fining employees who are discoveredoperating a vehicle while not using a seatbelt and utilizing variousdevices that prevent a vehicle from starting or moving unless theseatbelt is latched. However, imposing fines still requires some methodof determining whether an operator has properly fastened the vehicle'sseatbelt. Furthermore, an operator can easily defeat the seatbeltinterlocks by pulling out the seatbelt, fastening it, and sitting uponit. Therefore, a need exists for a system which determines not justwhether a vehicle's seatbelt is buckled, but that the seatbelt isfastened in the correct and intended manner.

BRIEF SUMMARY OF THE INVENTION

[0005] The present invention provides a system for detecting properusage of a seatbelt in a vehicle by an operator of the vehicle. Theseatbelt usage detection system includes a first communication devicearranged on the seatbelt and a second communication device. One of thefirst and second communication devices is a transmitter and the other ofthe first and second communication devices is a receiver. The receiverand transmitter are capable of establishing a communication link witheach other. The second communication device is arranged in the vehicleso as to be able to establish a communication link with the firstcommunication device of a predetermined signal strength upon properfastening of the seatbelt around the body of an operator. The systemalso includes a processing unit for monitoring the signal strength ofthe communication link between the first and second communicationdevices and for providing a signal that the seatbelt is unfastened whenthe signal strength is less than the predetermined signal strength.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a schematic diagram of an exemplary seatbelt detectionsystem in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0007] The present invention comprises a highly reliable and accuratesystem for confirming that the seatbelt of a vehicle is correctlyfastened around the operator. To this end, the system includes amechanism that detects the position of the seatbelt relative to both thevehicle steering mechanism and the vehicle operator and confirms thatthe seatbelt's position appropriately secures the operator as intended.The monitoring of the seatbelt position and confirmation that theseatbelt is properly fastened is performed not only when the vehicle isfirst started up, but also on a periodic or continuous basis thereafterto ensure that the operator does not subsequently remove the seatbelt.Moreover, since the present invention monitors the actual position ofthe seatbelt relative to both the operator and the steering wheel orsteering mechanism of the vehicle as opposed to simply monitoringwhether the seatbelt is latched, an operator cannot defeat the system bysitting on top of a latched seatbelt. As described in greater detailbelow, confirmation of proper use of the seatbelt can include additionalfeatures, which can make the system virtually impossible to defeat.Optionally, the system of the present invention can also include one ormore interlock mechanisms that carry out appropriate actions when theseatbelt is not properly fastened in use around the operator thusencouraging the operator to correctly fasten and use the seatbelt. Thus,the present invention provides a seatbelt usage detection system whichcan virtually guarantee that a vehicle operator has properly fastenedand is using the seatbelt around his body.

[0008] In the embodiment illustrated in FIG. 1, the system includescommunication devices that are arranged such that they are capable ofcommunicating through a wireless connection or link (e.g., via an IR orRF electromagnetic link) or a connection of a given electromagneticsignal strength only when the seatbelt is correctly fastened and in usearound the operator. In the illustrated embodiment, the communicationbetween the devices is via a wireless electromagnetic link in which thedevices can comprise a signaling device such as a transmitter 10 ortransceiver, which can be wireless, and a receiving device such as anantenna 12 or transceiver. For example, one electromagneticcommunication device can be affixed to the seatbelt and the otherelectromagnetic communication device can be located in a positionsubstantially in front of the operator such as on or embedded in thesteering wheel, steering mechanism or steering column. Theelectromagnetic communication devices can be selected such that theyhave a limited communication range (e.g., approximately 3-15 inches,plus or minus) such that for a transmission by the signaling device 10to be successfully received by the receiving device 12, the seatbelt andits corresponding electromagnetic communication device must bepositioned in front of the operator as consistent with the seatbelt'sappropriate use. If the seatbelt is positioned behind the operator, aswould occur if the seatbelt is unfastened or if the operator sits upon afastened belt, the communication between the electromagnetic receivingand signaling devices 12, 10 would be either outside the communicationrange of the devices or substantially blocked by the body of theoperator. Thus, by monitoring via a processing unit 14 such as anintegrated circuit or other similar device whether the receiving device12 is receiving the signal from the signaling device 10 or the strengthof the signal received, the detection system can detect whether theoperator has correctly fastened and is using the seatbelt. Of course, itwill be appreciated that all that is necessary are devices which arecapable of establishing a wireless communication link and as suchsignaling devices other than transmitters and receiving devices otherthan antennas can be used.

[0009] In order to help prevent subversion of the system, the system canbe configured with a plurality of electromagnetic communication devicessuch as transmitters 10 (e.g., three in the illustrated embodiment) onor encapsulated in the steering wheel or steering mechanism and aelectromagnetic communication device such as the antenna 12 can beaffixed to the seatbelt by interweaving an antenna wire into theseatbelt fabric. In this embodiment, the transmitters 10 are arrangedaround the circumference of the steering wheel such that when thesteering wheel is in various rotary positions only one of thetransmitters 10 is typically within range of the antenna 12 in theseatbelt. Rotating the steering wheel therefore causes differenttransmitters 10 to interact with the antenna 12. By configuring thetransmitters 10 so that they each emit a distinct signal, the processingunit 14 of the detection system can determine the direction of rotationof the steering wheel by comparing the sequence of signals received bythe antenna 12 with the known signal sequences indicating left or rightturns of the steering wheel. In this embodiment, a second mechanism fordetecting turning of the vehicle such as an acceleration sensor 16(e.g., an accelerometer) can be tied into the seatbelt detection system.In particular, the acceleration sensor 16 detects the left or rightacceleration typically associated with turning of the vehicle. Each timethe acceleration sensor 16 detects a left or right turn of the vehicle,the processing unit 14 can confirm whether the sequence of signalsreceived by the antenna 12 also indicates a rotation of the steeringwheel to either the right or left. If a confirmation of the correct leftor right turn is not provided by the signals received by the antenna 12,the processing unit 14 can provide an indication or a signal that thedetection system is not operating correctly or has been tampered with.

[0010] Thus, using this particular configuration for the seatbelt usagedetection system can help prevent the operator of the vehicle fromdefeating the system by attaching decoy transmitters (e.g., transmitters10) to the seatbelt since such an arrangement would provide a continuousreading of the decoy transmitter that would not change upon turning ofthe vehicle. Additionally, this configuration would prevent an operatorfrom simply arranging the seatbelt along side the steering wheel so thatthe antenna 12 is within the range of the transmitters 10 without theseatbelt actually being fastened since proper clocking of thetransmitters on the steering wheel would mean that in a straight aheadvehicle operation condition the wrong transmitter would be continuouslyread and depending on how the seatbelt was positioned the propersequence of transmitter readings would not be provided upon turning thevehicle.

[0011] Alternatively, the acceleration sensor can be eliminated and theprocessing unit 14 can be adapted to compare the rotation of thesteering wheel measured by interaction between the antenna 12 andtransmitters 10 with a predetermined estimate of steering wheel rotationof a like vehicle under similar circumstances. Where readings from theantenna and transmitters indicate that the operator has not rotated thesteering wheel for an unusually long period of time, the system canprovide a default or tamper signal.

[0012] With embodiments of the invention employing the antenna 12 in theseatbelt and one or more transmitters 10 in the steering wheel, theconnection between the antenna 12 and processing unit 14 can occuracross the seatbelt's latch and buckle, which thus acts as a switchwithin the antenna—processing unit circuit. Alternatively, if theantenna circuit is not made through the seatbelt buckle, the system caninclude a separate seatbelt buckle interlock 17 which provides a signalwhen the seatbelt is not buckled. This configuration helps preventtampering by use of decoy transmitters or deceptive positioning of theseatbelt as the unfastened status of the seatbelt buckle interlock 17breaks a circuit and thus alerts the processing unit 14 regardless ofany misleading interaction between the transmitters 10 and the antenna12.

[0013] Furthermore, the processing unit 14 may be configured toperiodically or continuously measure the electrical resistance of theantenna 12 in order to determine whether a decoy antenna routed in frontof the steering wheel has been connected to the seatbelt antenna 12 inorder to defeat the system. In this configuration, the resistancemeasurements of the antenna 12 are compared with prior measurements or apredetermined correct antenna resistance to verify that the antenna 12has not been tampered with.

[0014] An alternative embodiment of the invention involves affixing thetransmitter 10 to the seatbelt and the antenna 12 to the steering wheel.With this embodiment, monitoring of the steering wheel's motion may beaccomplished by arranging the two devices such that the antenna 12 movesfarther away from the transmitter 10 when the steering wheel is rotated,thus decreasing the strength of the signal received by the antenna 12.As discussed above, confirmation that the seatbelt is properlypositioned can be accomplished by comparing a turn indication from theacceleration sensor 16 with the signal fluctuations received by theantenna 12. If the processing unit 14 has not measured signalfluctuations indicative of turning of the steering wheel rotation, thenthe system can provide a default or tamper signal.

[0015] Instead of the combination of one or more transmitters and anantenna, in another embodiment of the invention, the seatbelt detectionsystem employs a scanning device and a target or mark that is arrangedso that it can be read by the scanning device only when the seatbelt iscorrectly fastened around the operator. For instance, a bar-code orother code reader can be affixed to the dashboard or steering wheel tomonitor an appropriate bar code or other machine readable code markaffixed to the seatbelt. The mark would be arranged on the seatbelt suchthat it is only within range of the scanning device when the seatbelt iscorrectly fastened around the operator.

[0016] A further alternative embodiment of the invention that might workin some situations involves employing a strain or tension sensor tomeasure force fluctuations imposed on the seatbelt retractor rollupshafts over time due to the shifting and jostling of the driver duringoperation. In order to determine whether the seatbelt is correctlyfastened around the operator, the processing unit can be adapted tocompare the monitor's measurements with predetermined values typicallyconsistent with the vehicle's operation. Where the seatbelt is notfastened or fastened incorrectly, such as behind the operator, thesensor would detect less strain and/or no changes in strain on theretractor shaft.

[0017] Once the seatbelt detection system determines that the seatbeltis positioned incorrectly around the operator, the system could beconfigured to initiate one or more interlock mechanisms 18 to encouragethe operator of the vehicle to fasten and use the seatbelt correctly.The invention can be configured with any number of specific mechanismsto accomplish this. For example, the processing unit 14 can be adaptedto signal an interlock mechanism 18 which inhibits or prevents operationof the vehicle when the seatbelt is determined to be unfastened orfastened incorrectly. The interlock mechanism 18 may take the form of aspeed governor 20 that prevents the engine from operating above idle inorder to restrict the vehicle to a safe speed. Alternatively, anignition lock or transmission lock 22 can be employed to prevent thevehicle from either being started or being moved until the seatbelt isfastened correctly.

[0018] To preclude potential safety issues, the interlock mechanism 18could include an emergency override feature that could override theeffects of any interlocks for a pre-determined time frame, long enoughto remedy an emergency. In order to prevent continuous use of theoverride feature in such a manner that subverts the purpose of theinvention, the override option can be configured to reset only uponshutting down and restarting the vehicle.

[0019] Another interlock mechanism 18 that could be used is a devicewhich communicates a signal to a remote monitoring station 24 when thedetection system determines that the seatbelt is not fastened properly.For example, an additional electromagnetic transmitter or transceivercan be actuated by the processing unit 14 when it is determined that theseatbelt is not properly fastened. The actuation of the transmitter ortransceiver produces a wireless signal that can be received at theremote monitoring station 24. An individual at the remote monitoringlocation may then contact the operator or, if so configured, disable thevehicle by a remote override control. Alternatively or additionally, aninterlock mechanism 18 consisting of a warning lamp 26 on the externalsurface of the vehicle that may be observed by non-occupants and/or asimilarly functioning external warning buzzer can be incorporated intothe seatbelt usage detection system of the present invention.

[0020] Additionally, an interlock mechanism 18 consisting of variousinternal warning devices can also be used. For example, an internalwarning lamp 28 located on the dashboard or elsewhere could indicatethat the seatbelt is not properly fastened. The location and brightnessof the lamp can be varied across a range from providing a subtle warningto a warning causing proper fastening of the seatbelt due to the lamp'sunpleasant effects. Alternatively, an internal warning buzzer could beemployed in the same manner.

[0021] To further prevent tampering with the system, a real-time clock30 can be incorporated into the processing unit 14 or interlockmechanism 18. The real-time clock 30 would record any abnormalities withthe system such as a power loss in the system that could be indicativeof tampering with the system. To ensure that the seatbelt usagedetection system is operating properly, the processing unit 14 also canbe adapted to perform periodic test routines. The testing routines mayoccur when the vehicle is first started and at subsequent timesthroughout vehicle operation. The testing routine indicators can becombined with the warning devices 20-28 mentioned above to indicate thatthe system may have been tampered with and that repair may be required.

[0022] Some Society of Automotive Engineer (SAE) standards that may berelevant to the present invention include (and which are incorporatedherein by reference):

[0023] SAE J128 November 94 “(R) Occupant Restraint SystemEvaluation—Passenger Cars and Light-Duty Trucks”

[0024] SAE J138 “Film Analysis Guides for Dynamic Studies of TestSubjects”

[0025] SAE J140 June 95 “(R) Seat Belt Hardware Test Procedures”

[0026] SAE J141 June 95 “(R) Seat Belt Hardware PerformanceRequirements”

[0027] SAE J339 June 94 “(R) Seat Belt Hardware Webbing Abrasion TestProcedure”

[0028] SAE J383 June 95 “(R) Motor Vehicle Seat Belt Anchorages-DesignRecommendations”

[0029] SAE J384 June 94 “(R) Motor Vehicle Seat Belt Anchorages—TestProcedure”

[0030] SAE J385 March 95 “Motor Vehicle Seat Belt Anchorages—PerformanceRequirements”

[0031] SAE J386 April 80 “Seat Belts for Construction Machines”

[0032] SAE J782b Motor Vehicle Seating Manual

[0033] SAE J800 June 94 “(R) Motor Vehicle Seat Belt AssemblyInstallation”

[0034] SAE J826 July 95 “(R) Devices for Use in Defining and MeasuringVehicle Seating Accommodation”

[0035] SAE J833 January 80 “USA Human Physical Dimensions”

[0036] SAE J879b Motor Vehicle Seating Systems

[0037] SAE J898 April 80 “Control Locations for Construction andIndustrial Equipment Design”

[0038] SAE J899 October 80 “Operator's Seat Dimensions of Off-RoadSelf-Propelled Work Machines”

[0039] SAE J1368 October 97 “Child Restraint Anchorages and AttachmentHardware”

[0040] SAE J1369 October 97 “Anchorage Provisions for Installation ofChild Restraint Tether Straps in Rear Seating Positions

[0041] SAE J1460-1 October 95 “(R) Human Mechanical Impact ResponseCharacteristics-Dynamic Response of the Human Abdomen”

[0042] SAE J1516 March 90 “Accommodation Tool Reference Point”

[0043] SAE J1517 March 90 “Driver Selected Seat Position”

[0044] SAE J1522 March 90 “Truck Driver Stomach Position”

[0045] SAE J1538 April 95 “(R) Glossary of Automotive InflatableRestraint Systems”

[0046] SAE J1630 March 95 “Driver or Passenger Airbag Module DeploymentTest Procedure”

[0047] SAE J1794 December 96 “SAE Restraint Systems Effluent TestProcedure”

[0048] SAE J1819 November 94 “(R) Securing Child Restraint Systems inMotor Vehicles”

[0049] SAE J1834 June 91 “Seat Belt Comfort, Fit and Convenience”

[0050] SAE J2074 June 93 “The Air Bag Systems in Your Car ‘What thePublic Needs to Know”’

[0051] SAE J2189 March 93 “Guidelines for Evaluating Child RestraintSystem Interactions with Deploying Airbags”

[0052] SAE J2431 October 97 “The Effects of Front-Mounted Accessories onAir Bag Sensors and Crashworthiness”

[0053] Additional relevant information can be found at the NationalTransportation Safety Board website www.ntsb.gov and the NationalHighway Traffic Safety Administration website www.nhtsa.dot.gov.

[0054] All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

[0055] The use of the terms “a” and “an” and “the” and similar referentsin the context of describing the invention (especially in the context ofthe following claims) are to be construed to cover both the singular andthe plural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

[0056] Preferred embodiments of this invention are described herein,including the best mode known to the inventors for carrying out theinvention. Of course, variations of those preferred embodiments willbecome apparent to those of ordinary skill in the art upon reading theforegoing description. The inventors expect skilled artisans to employsuch variations as appropriate, and the inventors intend for theinvention to be practiced otherwise than as specifically describedherein. Accordingly, this invention includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the invention unless otherwise indicated herein orotherwise clearly contradicted by context.

What is claimed is:
 1. A system for detecting proper usage of a seatbeltin a vehicle by an operator, the system comprising: a firstcommunication device arranged on the seatbelt; a second communicationdevice, wherein one of the first and second communication devices is atransmitter and the other of the first and second communication devicesis a receiver, the receiver and transmitter being capable ofestablishing a communication link with each other, the secondcommunication device being arranged in the vehicle so as to be able toestablish a communication link with the first communication device of apredetermined signal strength upon proper fastening of the seatbeltaround the body of an operator; and a processing unit for monitoring thesignal strength of the communication link between the first and secondcommunication devices and for providing a signal that the seatbelt isunfastened when the signal strength is less than the predeterminedsignal strength.